V=1L
27°C(300K) =>nr. moli=(V*p):(T*R)=(1*2,46):(300*0.082)=0,1moli
2,46atm
m=2.8g=>M=m:nr. moli=2.8: 0.1=28g/mol
C:85.71:12=7.14
H:(100-85.71):1=14.29
Impartim ultimele 2 relatii cu cel mai mic adica 7.14 si rezulta FB=CH2
FM=(FB)n ; n=M: MCH2=28:14=2=>FM=C2H4